Young Black men who have sex with men (YBMSM) are at extremely high risk for HIV infection in the U.S. If infection rates are not reduced, it is estimated that nearly 60% of YBMSM in the U.S. who are HIV-negative at age 18 will become infected by age 40. Rates of HIV infection among YBMSM in the Deep South are particularly high. The spread of HIV among YBMSM is driven by unprotected sex and unrecognized infections. Thus it is crucial to reduce sexual risk and increase HIV testing by conducting research that will lead to better interventions for YBMSM. The proposed study will support practical intervention development by examining sexual communication and its role in the spread of peer norms - one of the few factors consistently associated with sexual risk among YBMSM. Specifically, it aims to 1) investigate the content and processes of sexual communication among 18-24 year old YBMSM and their friends; 2) explore how sexual communication may influence risk behaviors and perceptions of peer norms regarding sexual risk and HIV testing; 3) explore sexual communication in two culturally distinct geographic regions where YBMSM are heavily impacted by HIV (Los Angeles, CA and Birmingham, AL); 4) and develop a culturally sensitive theoretical model of sexual communication among YBMSM that can be tested in further research and implemented in new and existing HIV prevention and testing interventions. To accomplish these aims, a three-phase qualitative study is proposed. In Phase 1 a team of peer ethnographers will collect field notes on sexual communication in venues where YBMSM socialize, providing an insider perspective on how sex and HIV are discussed. Peer ethnography can convey the linguistic nuances of communication in a more precise manner than other methods, which will also support the refinement of interview questions in the next phase. Phase 2 will utilize semi-structured interviews with 48 pairs of friends to examine the content and processes of conversations about sex and HIV testing as well as how peer norms are generated, transmitted, modified, or reinforced within these conversations. For example, preliminary data suggest that friends often reinforce the assumption that condom use and HIV testing are unnecessary in trusting relationships, even though a significant portion of HIV infections among MSM actually occur within primary partner relationships. In Phase 3, the theoretical model for sexual communication among YBMSM will be developed for implementation in existing and new dyad-level HIV prevention interventions. With a better understanding of peer sexual communication among YBMSM in culturally distinct regions such as Los Angeles and Birmingham, interventions can more effectively target the specific ways that such norms are transmitted and reinforced. Additionally, such interventions could leverage friends' natural concern for each others' well being by encouraging them to reinforce beneficial peer norms favoring condom use and HIV testing through explicit sexual health conversations, thereby drawing on the strengths of YBMSM and their friends to support the health of this population that is vulnerable to HIV infection. PUBLIC HEALTH RELEVANCE: Given that young Black men who have sex with men (YBMSM) are at extremely high risk for and at the forefront of HIV infection in the U.S., it is crucial to conduct research that will lead to better HIV prevention and testing interventions for this population. This innovative study will advance HIV prevention and practical intervention development by examining how communication between friends influences peer norms - the assumptions that individuals hold about how their peers think and behave regarding sexual risk and HIV testing. Existing and new interventions will be able to reduce HIV rates by leveraging this new knowledge to modify the peer norms that have been shown to influence sexual risk and HIV testing behaviors among YBMSM.